Donnie explains why brillliantly here:
In the same way, automated tools suck. They’re great once you understand the black box they hide from you, but ignoring that black box entirely is a route to disaster.
The understanding I have of the Linux operating system today – which admittedly is not worth comparing to what, say, Donnie knows about it – is all due to my early (and ongoing) experiences with Gentoo.
I’ve been known to tell audiences that I originally chose Gentoo because of the community (the nicest and most helpful I’ve encountered thus far) and the quality of documentation produced by that community (it’s absurdly good), and I haven’t been lying. Looking back, however, the single most important impact of my choice has been a greater understanding of the Linux internals. As Donnie says, at some point or another, things are going to break. If you’ve run Gentoo, you’ll understand why, because you’ve built the system by hand.
Most people, of course, aren’t interested in this level of appreciation, content to outsource that understanding to other people. And I suppose I am a bit of an anomaly, since one of the first things I’d do if I won Powerball would be to build my own car. But for those of you that are interested in Linux, there aren’t many better places to start than Gentoo. Even if Jeff tells you it’s like banging rocks together 😉